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Chordata is the third-largest phylum of the animal kingdom (behind only the protostomic phyla Arthropoda and Mollusca) and is also one of the most ancient taxons. Chordate fossils have been found from as early as the Cambrian explosion over 539 million years ago. [11]
Late Devonian: 375 million years ago, 75% of species lost, including most trilobites. End Permian, The Great Dying: 251 million years ago, 96% of species lost, including tabulate corals, and most trees and synapsids. End Triassic: 200 million years ago, 80% of species lost, including all conodonts. End Cretaceous: 66 million years ago, 76% of ...
The time of appearance of the earliest eutherians has been a matter of controversy. On one hand, recently discovered fossils of Juramaia have been dated to 160 million years ago and classified as eutherian. [73] Fossils of Eomaia from 125 million years ago in the Early Cretaceous have also been classified as eutherian. [74]
The 3D scans revealed two nearly complete specimens of Arthropleura that lived 300 million years ago. Both fossilized animals still had most of their legs, and one of them had a complete head ...
A major event in proboscidean evolution was the collision of Afro-Arabia with Eurasia, during the Early Miocene, around 18–19 million years ago, allowing proboscideans to disperse from their African homeland across Eurasia and later, around 16–15 million years ago into North America across the Bering Land Bridge.
They first appeared in the fossil record around 66 million years ago, soon after the Cretaceous–Paleogene extinction event that eliminated about three-quarters of plant and animal species on Earth, including most dinosaurs. [25] [26] One of the last Plesiadapiformes is Carpolestes simpsoni, having grasping digits but not forward-facing eyes ...
A six-mile-long asteroid, which struck Earth 66 million years ago, wiped out the dinosaurs and more than half of all life on Earth. The impact left a 124-mile-wide crater underneath the Gulf of ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...